CN113465810A

CN113465810A - Pressure sensor for evaporative fuel leak detector

Info

Publication number: CN113465810A
Application number: CN202110329919.5A
Authority: CN
Inventors: 岸辽佑; 加藤康夫; 伊藤智启
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2020-03-31
Filing date: 2021-03-29
Publication date: 2021-10-01
Also published as: JP2021162446A; JP7251509B2; US20210302265A1; US11493402B2

Abstract

A pressure sensor (1) for an evaporative fuel leak detector is used to check for leaks in fuel tanks and canisters. The pressure sensor includes a sensor unit (2), a housing (3), and a sealing resin (4). The sensor unit (2) has a pressure receiving section (21), a plurality of conductive terminals (213), and a molded resin section (22). The housing has a fluid flow path (31) and a housing recess (32). Each remaining inner wall surface (323B) of the housing recess, excluding the inner wall surface (323A) on the conductive terminal side, is provided with an inclined surface (327) and a vertical surface (328) in a cross section along an axial direction L perpendicular to the pressure receiving surface (210) of the sensor unit. The inclined surface is inclined inward as it goes toward the pressure receiving side L1. The vertical surface extends from an end on the pressure receiving side L1 of the inclined surface to define a filling gap (34) filled with sealing resin between a side surface (222) of the molded resin portion (22) and the vertical surface.

Description

Pressure sensor for evaporative fuel leak detector

Technical Field

The present disclosure relates to a pressure sensor for an evaporative fuel leak detector.

Background

In a vehicle having an internal combustion engine, hydrocarbon fuel (such as gasoline, high octane, and light oil) serving as liquid fuel in the internal combustion engine is stored in a fuel tank. Vaporized fuel is produced in the fuel tank. An evaporated fuel treatment device having a canister (canister) capable of adsorbing evaporated fuel is used so as not to release the evaporated fuel to the outside.

In the evaporated fuel treatment apparatus, an evaporated fuel leak detector for checking airtightness of the fuel tank and the canister is used. The evaporated fuel leak detector is provided with: a depressurizing pump for depressurizing an inside of the fuel tank and an inside of the canister; a solenoid valve (solenoid valve) configured to switch the connection of the gas phase of the canister to atmosphere or a pressure reducing pump; and a pressure sensor provided in a first pipe between the pressure-reducing pump and the solenoid valve to detect a pressure in the first pipe reduced in pressure by the pressure-reducing pump.

Furthermore, a bypass pipe is connected to the first pipe and a second pipe between the canister and the solenoid valve to bypass (so to speak) the solenoid valve so that a predetermined leak state is created by an orifice provided in the bypass pipe. Then, it is judged whether or not the fuel tank and the canister leak based on the leak state from the orifice provided in the bypass pipe. An evaporated fuel leak detector is described in patent document 1, for example.

Documents of the prior art

Patent document

[ patent document 1] JP 2015-

Disclosure of Invention

The pressure sensor shown in patent document 1 and the like includes a sensor unit having a pressure receiving portion, a housing in which a housing recess portion for accommodating a fluid flow path of a first pipe and the sensor unit is formed, and a sealing resin disposed in a gap of the housing recess portion accommodating the sensor unit. The sensor unit is fixed to the housing recess, and a periphery of the sensor unit is sealed by the sealing resin, so that a pressure applied from the fluid flow path to a pressure receiving surface of a pressure receiving portion of the sensor unit is detected. The pressure receiving portion of the sensor unit converts a pressure applied to the pressure receiving surface into a strain, and detects a change in voltage caused by the strain.

Since the sealing resin disposed in the case recess fixes the sensor unit to the housing, the sealing resin is disposed so as not to reach a rear side of the sensor unit on an opposite side of the pressure receiving surface of the pressure receiving portion. Further, in the conventional pressure sensor, in order to guide the arrangement of the sensor unit into the housing recess and facilitate the injection of the sealing resin into the housing recess, an inclined surface is formed in an inner wall surface of the housing recess up to a position facing a side surface of the sensor unit. The housing recess is filled with a sealing resin along the inclined surface of the housing recess, and the thickness of the filling resin facing the side surface of the sensor unit becomes thinner with the direction toward the pressure receiving surface of the pressure receiving portion (i.e., toward the bottom side of the housing recess).

Due to such a structure of the sealing resin, when the pressure sensor is heated or cooled, the thermal stress applied from the sealing resin to the sensor unit increases as the thickness of the sealing resin increases. Since the thermal stress applied from the sealing resin to the sensor unit is uneven, the sensor unit may be unevenly deformed, and stress is also generated in the pressure receiving portion, so that an error may occur in the pressure detection of the pressure sensor.

The present disclosure has been made in view of the above problems, and provides a pressure sensor for an evaporated fuel leak detector, in which an error in pressure detection can be effectively reduced.

According to an example of the present disclosure, a pressure sensor is used for an evaporated fuel leak detector configured to detect a leak of evaporated fuel in an evaporated fuel treatment apparatus including a fuel tank and a canister for adsorbing evaporated fuel discharged from the fuel tank. The pressure sensor includes a sensor unit, a housing, and a sealing resin. The sensor unit includes a pressure receiving portion configured to detect a pressure of a fluid applied to a pressure receiving surface, a plurality of conductive terminals provided at the pressure receiving portion and made of a conductive material, and a molded resin portion covering an outer surface of the pressure receiving portion other than the pressure receiving surface. The housing is provided with a fluid flow path through which a fluid is introduced to the pressure receiving surface, and a housing recess that accommodates the sensor unit therein and is connected to the fluid flow path. The sealing resin is filled into the housing recess in which the sensor unit is accommodated to cover a surface of the molding resin portion disposed in the housing recess. The housing has an annular inner wall surface that defines the housing recess and surrounds a side surface of the molded resin portion, and the annular inner wall surface of the housing includes a first inner wall surface and a plurality of second inner wall surfaces that intersect each other, wherein the first inner wall surface is located on a conductive terminal side where a plurality of conductive terminals are arranged.

When a direction in which the pressure receiving surface is arranged to be exposed from the housing recess is a pressure receiving side and a direction opposite to the pressure receiving side of the housing recess is a rear side, in a cross section along a direction perpendicular to the pressure receiving surface, the second inner wall surface has an inclined surface that is inclined inward as it goes toward the pressure receiving side, and a vertical surface adjacent to the pressure receiving side of the inclined surface, the vertical surface extending in the direction perpendicular to the pressure receiving surface to define a sealing resin-filled gap between a side surface of the molded resin portion and the vertical surface.

In the pressure sensor of the evaporated fuel leak detector according to the example, the sealing resin filled in the housing concave portion covers a surface of the mold resin portion disposed in the housing concave portion. With this configuration, electromagnetic noise or heat generated from the motor of the pressure-reducing pump and solenoid noise of the solenoid valve arranged around the pressure sensor of the pressure-reducing leak check module hardly reach the sensor unit from the rear side of the sensor unit.

Each second inner wall surface of the housing recess of the present example is provided with an inclined surface and a vertical surface in a cross section along an axial direction L perpendicular to the pressure receiving surface. The inclined surface is inclined inward toward the pressure receiving side. The vertical surface extends from an end of the pressure receiving side of the inclined surface to define a filling gap filled with sealing resin between a side surface of the molded resin portion and the vertical surface. With this configuration, the thickness of the sealing resin filled in the filling gap between the side surface of the molded resin portion and the vertical surface of the housing recess can be made substantially uniform in the axial direction L.

Due to such a structure of the sealing resin, when the pressure sensor is heated, the thermal stress applied from the sealing resin to the pressure receiving portion of the sensor unit becomes more uniform. Therefore, the pressure detection of the pressure receiving portion is less affected by the thermal stress.

Therefore, the pressure sensor of the evaporated fuel leak detector according to the present example can reduce the error of pressure detection, and can improve the accuracy of pressure detection.

Drawings

The above and other objects, features and advantages of the present disclosure will be more clearly understood through the following detailed description with reference to the accompanying drawings. In the drawings, there is shown in the drawings,

fig. 1 is a diagram showing the configuration of a pressure-reducing leak check module using a pressure sensor and an evaporated fuel processing apparatus according to a first embodiment;

FIG. 2 is a schematic cross-sectional view illustrating a pressure sensor taken along cross-section II-II of FIG. 4 in accordance with a first embodiment;

FIG. 3 is a schematic cross-sectional view illustrating a pressure sensor taken along the cross-section III-III of FIG. 4 according to a first embodiment;

fig. 4 is a plan view showing the pressure sensor according to the first embodiment in a state not filled with the sealing resin;

FIG. 5 is a schematic cross-sectional view showing a pressure sensor according to a second embodiment taken along the cross-section V-V of FIG. 7;

FIG. 6 is a schematic cross-sectional view illustrating a pressure sensor taken along the cross-section VI-VI of FIG. 7 in accordance with a second embodiment;

fig. 7 is a plan view showing a pressure sensor according to a second embodiment in a state not filled with a sealing resin;

fig. 8 is an enlarged view showing a part of fig. 5 according to the second embodiment;

fig. 9 is an enlarged view showing another pressure sensor according to the second embodiment;

fig. 10 is an enlarged view showing another pressure sensor according to the second embodiment;

FIG. 11 is a schematic cross-sectional view showing a pressure sensor according to a third embodiment taken along the cross-section XI-XI of FIG. 13;

FIG. 12 is a schematic cross-sectional view illustrating a pressure sensor taken along cross-section XII-XII of FIG. 13, in accordance with a third embodiment;

fig. 13 is a plan view showing a pressure sensor according to a third embodiment in a state not filled with a sealing resin;

fig. 14 is an enlarged view showing a part of fig. 11 according to the third embodiment;

FIG. 15 is a schematic cross-sectional view showing a pressure sensor according to a fourth embodiment taken along the cross-section XV-XV of FIG. 17;

FIG. 16 is a schematic cross-sectional view illustrating a pressure sensor taken along cross-section XVI-XVI of FIG. 17 in accordance with a fourth embodiment;

fig. 17 is a plan view showing a pressure sensor according to a fourth embodiment in a state not filled with a sealing resin;

fig. 18 is a plan view showing the pressure sensor according to the fourth embodiment in a state where the sensor unit and the sealing resin are not filled.

Detailed Description

Preferred embodiments of a pressure sensor of an evaporated fuel leak detector will be described with reference to the accompanying drawings.

< first embodiment >

As shown in fig. 1, the pressure sensor 1 for an evaporated fuel leak detector (hereinafter simply referred to as "pressure sensor 1") of the present embodiment is used for an evaporated fuel treatment apparatus 6, and the evaporated fuel treatment apparatus 6 includes a fuel tank 61 and a canister 62 configured to adsorb evaporated fuel discharged from the fuel tank 61. The evaporated fuel leak detector detects an evaporated fuel leak in an apparatus including the fuel tank 61 and the canister 62 by leak check. In other words, the evaporated fuel leak detector is configured to determine whether there is a possibility of an evaporated fuel leak by using a leak check.

As shown in fig. 2 to 4, the pressure sensor 1 includes a sensor unit 2, a housing 3, and a sealing resin 4. The sensor unit 2 includes: a pressure receiving portion 21 for detecting the pressure of the fluid R applied to the pressure receiving surface 210; and a mold resin portion (mold resin portion)22 covering a surface of the pressure receiving portion 21 other than the pressure receiving surface 210. The housing 3 includes a fluid flow path 31 for introducing the fluid R to the pressure receiving surface 210, and a housing recess 32 connected to the fluid flow path 31. The sensor unit 2 is accommodated in the case recess 32 of the housing 3. The sealing resin 4 is arranged in the housing recess 32, and is configured to cover at least a rear surface 223 of the molding resin portion 22 on the opposite side of the pressure receiving surface 210.

The pressure sensor 1 of this embodiment will be described in detail below. The depressurization leak check module 10 will now be described.

As shown in fig. 1, the pressure sensor 1 is attached to a vehicle evaporated fuel processing apparatus 6 having a fuel tank 61 and a canister 62, and is part of a pressure-reducing leak check module (ELCM)10, and the pressure-reducing leak check module (ELCM)10 is configured as an evaporated fuel leak detector to check for leaks in the fuel tank 61 and the canister 62. The pressure-reducing leak inspection module 10 is provided with: a depressurizing pump 51 for depressurizing the inside of the fuel tank 61 and the inside of the canister 62 to a depressurized state; a solenoid valve 52 configured to switch the connection of the canister 62 to be connected to an atmosphere pipe 55 open to the atmosphere or to the pressure reducing pump 51; and a pressure sensor 1 arranged to detect the pressure within the first conduit 53A. The inside of the first pipe 53A is depressurized by the depressurizing pump 51.

The pressure reducing pump 51, the solenoid valve 52, the pressure sensor 1, and the like are electrically connected to the controller 8. The pressure sensor 1 is disposed in a first pipe 53A connecting the pressure-reducing pump 51 and the solenoid valve 52. The canister 62 and the solenoid valve 52 are connected by a second pipe 53B. A bypass pipe 54 bypassing the solenoid valve 52 is connected to the first pipe 53A and the second pipe 53B. An orifice 541 is provided in the bypass pipe 54.

The fuel tank 61 and the canister 62 are connected by a steam pipe 63, and the evaporated fuel is discharged through the steam pipe 63. The steam pipe 63 may be provided with a sealing valve 631, and the sealing valve 631 opens the steam pipe 63 when the evaporated fuel in the fuel tank 61 is discharged to the canister 62. Canister 62 and intake pipe 71 of engine (internal combustion engine) 7 are connected by drain pipe (purge pipe) 64. A drain valve 641 is provided in the drain pipe 64. When the fuel component is discharged from the canister 62 to the intake pipe 71, the drain valve 641 opens the drain pipe 64.

The pressure reducing pump 51 is also referred to as a vacuum pump, and can pump down the canister 62, the fuel tank 61, the first pipe 53A, the second pipe 53B, and the bypass pipe 54. When the fuel tank 61, the canister 62, and the like are suctioned by the pressure-reducing pump 51, the purge valve 641 of the purge pipe 64 is closed.

The solenoid valve 52 is made of an electromagnetic valve (electromagnetic valve). The solenoid valve 52 is switchable between an open position 521, in which the inside of the canister 62 is open to the atmosphere, and a pressure-reducing position 522, in which the inside of the canister 62 is connected to the pressure-reducing pump 51. When the solenoid valve 52 is switched to the pressure-reducing position 522, the first pipe 53A and the second pipe 53B communicate with each other via the solenoid valve 52, so that the first pipe 53A, the second pipe 53B, and the bypass pipe 54 communicate with each other.

An orifice 541 provided in the bypass pipe 54 is used to simulate a predetermined leak condition indicating an upper limit value of a leak allowable range in a path drawn by the pressure-reducing pump 51. The orifice 541 of the present embodiment simulates a state in which a hole having a diameter of 0.5mm is formed in the path of the suction air. When a pseudo leakage state is formed through the orifice 541, the solenoid valve 52 is in the open position 521, and a path circulating from the pressure-reducing pump 51 through the first pipe 53A, the solenoid valve 52, and the bypass pipe 54 passing through the orifice 541 is evacuated. Therefore, the pressure is detected by the pressure sensor 1. In this state, the pressure detected by the pressure sensor 1 becomes a pressure of a leakage allowable reference value.

On the other hand, when leak detection is performed, the solenoid valve 52 is located at the pressure-reducing position 522, so that the pressure-reducing pump 51 evacuates the inside of the fuel tank 61, the canister 62, and the like. At this time, if the pressure detected by the pressure sensor 1 is equal to or less than the leakage allowable reference value, it is determined that there is no leakage, and if the pressure detected by the pressure sensor 1 exceeds the leakage allowable reference value, it is determined that there is a leakage.

The solenoid valve 52 is normally in the open position 521 and the interior of the canister 62 can be maintained at atmospheric pressure under normal conditions.

Next, the evaporated fuel treatment device 6 will be described.

As shown in fig. 1, in the vehicle, the evaporated fuel treatment device 6 is used so that the evaporated fuel, which is a part of the gas in the fuel tank 61, is not released into the atmosphere. The evaporated fuel in the fuel tank 61 is stored in the canister 62 and then discharged to the intake pipe 71 of the engine 7, or bypasses the canister 62 and is discharged to the intake pipe 71 of the engine 7. The fuel component of the evaporated fuel is then used for combustion in the engine 7.

The flow rate of combustion air a supplied from the intake pipe 71 to the engine 7 is adjusted by operating a throttle valve 72 disposed in the intake pipe 71. The engine 7 is provided with a fuel injection device (not shown) that injects fuel F supplied from a fuel tank 61.

Next, the fuel tank 61 will be described.

As shown in fig. 1, the fuel tank 61 stores fuel F for combustion operation of the engine 7. The fuel tank 61 includes a fuel supply port 611, a vapor port 612, and a fuel pump (not shown). The fuel supply port 611 is for receiving fuel F filled into the fuel tank 61 from the outside. Steam port 612 is connected to steam pipe 63. The fuel pump is used when supplying fuel F to the fuel injection device of the engine 7. The fuel pump supplies the liquid-phase fuel F of the fuel tank 61 to the fuel injection device.

The fuel lid 613 is provided at the fuel supply port 611 of the fuel tank 61, and closes the fuel supply port 611 during normal operation. The fuel cover 613 is removed during refueling to open the fuel supply port 611. Further, the vehicle is provided with a fuel lid (not shown) that covers the fuel lid 613 during normal operation. The fuel cap enables the operation of removing/attaching the fuel cap 613 during refueling.

The canister 62 will be described.

As shown in FIG. 1, canister 62 includes a canister housing 621 and an adsorbent 622, such as activated carbon. An adsorbent 622 is disposed in the canister housing 621 and adsorbs vaporized fuel (i.e., fuel vapor). The canister housing 621 of canister 62 includes an inlet 623, an outlet 624, and a pressure relief 625. The inlet 623 is connected to the steam pipe 63 and allows gas to enter. The outlet 624 is connected to the drainpipe 64 and allows the fuel components to be separated. The pressure release port 625 is connected to the second pipe 53B and the solenoid valve 52 so as to be opened to the atmosphere. When the vaporized fuel (i.e., gaseous fuel) is discharged from the gas phase of the fuel tank 61 to the canister 62, and when the solenoid valve 52 is in the open position 521, the pressure release port 625 is opened to the atmosphere through the atmosphere pipe 55. In the canister 62, the fuel component in the evaporated fuel is adsorbed by the adsorbent 622, while the pressure in the canister 62 becomes equal to the atmospheric pressure.

The fuel components adsorbed by the adsorbent 622 of the canister 62 pass through the purge pipe 64 and are discharged to the intake pipe 71 of the engine 7. At this time, the solenoid valve 52 is in the open position 521, the pressure release port 625 of the canister 62 is open to the atmosphere, and the drain pipe 64 is opened by the drain valve 641. The fuel components adsorbed by the adsorbent 622 are discharged to the intake pipe 71 of the engine 7 by the airflow caused by the pressure difference between the pressure of the atmosphere entering the canister 62 through the pressure release port 625 and the negative pressure in the intake pipe 71.

Next, the sensor unit 2 of the pressure sensor 1 will be described.

As shown in fig. 2 and 3, the pressure receiving portion 21 of the sensor unit 2 is constructed by using a piezoresistive semiconductor. Piezoresistive semiconductors utilize the piezoresistive effect, which is a phenomenon in which resistance changes when a substance is stressed. The pressure receiving portion 21 includes a circuit portion 211 and an insulating gel (insulating gel)212 surrounding the circuit portion 211, and a detection circuit such as a Wheatstone bridge (Wheatstone bridge) is formed in the circuit portion 211. The sensor terminals are led out from the circuit portion 211 to the outside of the gel 212 and the molded resin.

In the present embodiment, in the axial direction L of the housing 3, the side of the pressure receiving portion 21 where the pressure receiving surface 210 is located is referred to as a pressure receiving side L1, and the side opposite to the pressure receiving surface 210 is referred to as a rear side L2. In other words, the side of the housing recess 32 on which the pressure receiving surface 210 of the pressure receiving portion 21 is disposed is referred to as a pressure receiving side L1, and the side of the housing recess 32 opposite to the pressure receiving side L1 is referred to as a rear side L2.

The molded resin portion 22 of the sensor unit 2 is made of a thermoplastic resin or the like having excellent heat resistance. The pressure receiving surface 210 of the pressure receiving portion 21 is formed as the front surface of the pressure receiving portion 21, which is not covered by the molded resin portion 22. The pressure receiving surface 210 is located at a position recessed from the surface of the molded resin portion 22 to the rear side L2. The molded resin portion 22 covers a portion of the pressure receiving portion 21 other than the front surface where the pressure receiving surface 210 is located.

As shown in fig. 2 and 3, the molded resin portion 22 of the present embodiment includes a noise removal capacitor 23, and the noise removal capacitor 23 is configured to remove noise (electromagnetic noise) that affects pressure detection of the sensor unit 2. The capacitor 23 is made of a monolithic ceramic capacitor or the like in which a plurality of electrodes and dielectrics are laminated. The capacitor 23 has a characteristic of blocking a direct current while passing an alternating current. The capacitor 23 is configured to remove an alternating current component superimposed on the circuit unit 211 by grounding the circuit portion 211 of the pressure receiving section 21 or the like. The wiring of the circuit unit 211, the capacitor 23, and the like is electrically connected to the plurality of conductive terminals 213.

Next, the housing 3 of the pressure sensor 1 will be described in detail.

As shown in fig. 2 and 3, the housing 3 of the pressure sensor 1 accommodates the sensor unit 2 and is configured to introduce the fluid R into the pressure receiving portion 21 of the sensor unit 2. The case 3 is provided in a pressure-reducing leak check module 10, as shown in fig. 1, the pressure-reducing leak check module 10 including a pressure-reducing pump 51, a solenoid valve 52, and the like. The fluid flow path 31 of the housing 3 is formed in the axial direction L of the housing 3. The axial direction L of the housing 3 is a direction perpendicular to the pressure receiving surface 210 of the pressure receiving portion 21 of the sensor unit 2. The pressure of the fluid R flowing through the fluid flow path 31 is vertically applied from the fluid flow path 31 to the pressure receiving surface 210 of the pressure receiving portion 21.

The case recess 32 of the housing 3 is sized to accommodate the sensor unit 2. The case recess 32 has a fitting portion 321 into which the pressure receiving portion 222A of the molded resin portion 22 of the sensor unit 2 is fitted, and a filling portion 322 connected to the fitting portion 321 to fill the sealing resin 4. Further, an enlarged flow path portion 311 is formed between the fitting portion 321 and the fluid flow path 31, and in the enlarged flow path portion 311, the flow of the fluid R flowing from the fluid flow path 31 toward the pressure receiving surface 210 of the pressure receiving portion 21 is enlarged.

The pressure receiving portion 222A positioned on the side surface 222 of the molded resin portion 22 closer to the side where the pressure receiving surface 210 is located is fitted into the fitting portion 321 of the housing concave portion 32. Since the molded resin portion 22 of the sensor unit 2 is fitted into the fitting portion 321, the sealing resin 4 is prevented from entering the fluid flow path 31 when the sealing resin 4 is filled in the filling portion 322 of the housing concave portion 32.

As shown in fig. 3 and 4, the inner wall surface 323 of the filling part 322 defining the housing recess 32 is made of an inner wall surface 323A on the conductive terminal side and a remaining inner wall surface 323B except for the inner wall surface 323A on the conductive terminal side. The inner wall surface 323A on the conductive terminal side is arranged in one direction in a plane parallel to the pressure receiving surface 210 of the pressure receiving portion 21 of the housing recess 32, and the remaining inner wall surfaces 323B are arranged in the remaining three directions in the plane. At an end of the pressure receiving side L1 of the inner wall surface 323A on the conductive terminal side, a bottom surface 324 parallel to the pressure receiving surface 210 is formed in a cross section along the axial direction L perpendicular to the pressure receiving surface 210. As shown in fig. 3, the bottom surface 324 is located between the side surface 222 of the molded resin portion 22 of the sensor unit 2 and the inner wall surface 323A on the conductive terminal side.

The housing 3 is provided with a plurality of housing-side terminals 33, and the plurality of housing-side terminals 33 are in contact with the plurality of conductive terminals 213 and are electrically conductive. The plurality of conductive terminals 213 of the pressure receiving portion 21 of the sensor unit 2 are electrically connected to the power supply, the controller 8, and the like arranged outside the step-down leakage inspection module 10 via the plurality of case-side terminals 33.

As shown in fig. 4, in the molded resin portion 22 of the sensor unit 2, chamfered portions 225 or curved surface portions 226 are formed at four corner portions in a plane parallel to the pressure receiving surface 210 of the pressure receiving portion 21. The inner wall surface 323 of the case recess 32 of the housing 3 is formed in a shape corresponding to the shape of the sensor unit 2 in a plane parallel to the pressure receiving surface 210. In a plane parallel to the pressure receiving surface 210, chamfered portions 323C or curved portions 323D are formed at corner portions of three remaining inner wall surfaces 323B on the inner wall surface 323. The remaining inner wall surface 323B is provided with a chamfered portion 323C and a curved surface portion 323D.

The sealing resin 4 will be described.

As shown in fig. 2 and 3, the sealing resin 4 is made of a thermosetting resin such as an epoxy resin. The sealing resin 4 is used to fix the sensor unit 2 to the housing 3 and to seal the outer periphery of the sensor unit 2. After the sensor unit 2 is fitted in the fitting portion 321 of the case concave portion 32 of the housing 3, the sealing resin 4 is filled in the filling portion 322 of the case concave portion 32. The sensor unit 2 is completely covered with the sealing resin 4 filled in the filling portion 322 of the case concave portion 32. In other words, when the sensor unit 2 is disposed in the case recess 32, the molded resin part 22 of the sensor unit 2 is exposed in the filling part 322 of the case recess 32, and then the surface of the molded resin part 22 is covered and sealed with the sealing resin 4.

The sealing resin 4 is filled in the filling part 322 of the case recess 32 to cover the rear side part 222B except for the pressure receiving side part 222A and the entire rear surface 223 in the side surface 222 of the molded resin part 22 of the sensor unit 2. With this configuration, electromagnetic noise, heat, and the like generated from the devices arranged around the pressure sensor 1 are difficult to reach the pressure receiving portion 21 of the sensor unit 2.

The material of the pressure sensor 1 will be described.

In one comparative pressure sensor, the rear surface of the sensor unit was exposed to the outside without being covered with the sealing resin. In this comparative pressure sensor, there may be two factors that make it difficult to ensure airtightness: peeling (peeling) at an interface between the molded resin portion of the sensor unit and the sealing resin, and peeling at an interface between the housing and the sealing resin. Further, due to these two types of interfaces, peeling can be easily generated.

As shown in fig. 2 and 3, in the vicinity of the sensor unit 2 of the pressure sensor 1 of the present embodiment, since the sealing resin 4 covers and seals the entire molding resin portion 22, the interface between the molding resin portion 22 and the sealing resin 4 is not exposed to the outside around the sensor unit 2. In this case, only the interface between the housing 3 and the sealing resin 4 is exposed to the outside around the sensor unit 2. Therefore, the only factor for ensuring the airtightness of the pressure sensor 1 due to peeling is the interface between the case 3 and the sealing resin 4.

In the present embodiment, since the capacitor 23 is incorporated into the molded resin portion 22, a resin material having a small linear expansion coefficient is intentionally used so as to approach the linear expansion coefficient of the capacitor 23. Further, the sealing resin 4 of the present embodiment is prepared by adding a filler as an inorganic material to a curable resin material, thereby intentionally reducing the linear expansion coefficient. In other words, the sealing resin 4 of the present embodiment contains a curable resin material and a filler added to the resin material as an inorganic material. The filler content in the sealing resin 4 is in the range of 40% to 90%.

When the content ratio of the filler in the sealing resin 4 increases, the linear expansion coefficient becomes lower. For example, when the filler content in the sealing resin 4 is 40% by mass or more, the linear expansion coefficient can be effectively reduced. On the other hand, if the mass content of the filler in the sealing resin 4 exceeds 90%, the content of the filler becomes excessively large, and the adhesiveness of the sealing resin 4 may deteriorate.

(function and Effect)

The pressure sensor 1 of the evaporated fuel leak detector of the present embodiment is used for the pressure-reducing leak check module 10. In the pressure sensor 1, the sealing resin 4 disposed in the case recess 32 covers the rear side portion 222B in the side surface 222 of the molded resin part 22 of the sensor unit 2 and all the rear surfaces 223 of the molded resin part 22. With this configuration, electromagnetic noise generated from the motor of the pressure-reducing pump 51 and solenoid noise of the solenoid valve 52 arranged around the pressure sensor 1 of the pressure-reducing leak check module 10 are difficult to reach the sensor unit 2 from the rear side L2 of the sensor unit 2. Further, it is possible to prevent heat generated from the motor of the pressure-reducing pump 51, the solenoid of the solenoid valve 52, and the like from reaching the sensor unit 2 from the rear side L2 of the sensor unit 2. Therefore, the pressure sensor 1 is less susceptible to electromagnetic noise and heat, and the factors that cause detection errors in the pressure sensor 1 can be effectively reduced.

Therefore, according to the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the pressure detection accuracy can be improved.

< second embodiment >

The pressure sensor 1 of the present embodiment is different from the pressure sensor 1 of the first embodiment, particularly in the shape of the housing 3. As shown in fig. 5 to 7, the pressure sensor 1 of the second embodiment also includes a sensor unit 2, a housing 3, and a sealing resin 4. The sensor unit 2 includes a pressure receiving portion 21 configured to detect the pressure of the fluid R applied to the pressure receiving surface 210, a plurality of conductive terminals 213 provided at the pressure receiving portion 21 and made of a conductive material, and a molded resin portion 22 covering an outer surface of the pressure receiving portion 21 other than the pressure receiving surface 210. The basic configuration of the housing 3 and the sealing resin 4 is similar to that of the first embodiment, and explanation of the same parts is partially or entirely omitted.

An annular inner wall surface 323 that surrounds the side surface 222 of the resin section 22 and defines the case recess 32 is made of a conductive terminal-side inner wall surface 323A and a remaining inner wall surface 323B, similar to the structure of the first embodiment. When the remaining inner wall surface 323B is viewed in a cross section along the axial direction L perpendicular to the pressure receiving surface 210, the remaining inner wall surface 323B is provided with a parallel stepped surface 326 parallel to the pressure receiving surface 210, as shown in fig. 8.

As shown in fig. 8, the parallel stepped surface 326 is configured to prevent peeling occurring at the exposed position of the rear side L2 of the interface between the remaining inner wall surface 323B of the case recess 32 and the sealing resin 4 from extending further to the pressure receiving side L1. As shown in fig. 7 and 8, the parallel stepped surface 326 is formed on the remaining inner wall surface 323B arranged in three directions in a plane parallel to the pressure receiving surface 210 in the inner wall surface 323 of the housing recess 32. The parallel stepped surface 326 of each remaining inner wall surface 323B is formed parallel to the pressure receiving surface 210.

As shown in fig. 5 and 6, all the parallel stepped surfaces 326 of each remaining inner wall surface 323B are positioned on the rear side L2 as compared with the tip end of the rear surface 223 positioned on the rear side L2 in the molding resin section 22. Further, the sealing resin 4 is filled up to the position of the rear side L2 beyond the parallel stepped surface 326 of each remaining inner wall surface 323B in the case recess 32. In other words, the surface 41 of the rear side L2 of the sealing resin 4 exceeds the parallel stepped surface 326 of each remaining inner wall surface 323B on the rear side L2.

By filling the sealing resin 4 to a position of the rear side L2 beyond the parallel stepped surface 326, the thickness of the sealing resin 4 disposed on the rear side L2 of the molding resin section 22 can be made equal to or greater than a certain thickness. If the parallel stepped surface 326 is used as a mark of the filling position of the sealing resin 4 and the entire parallel stepped surface 326 is buried in the sealing resin 4, the thickness of the sealing resin 4 may be set to a certain thickness or more.

As shown in fig. 8, in a cross section along the axial direction L perpendicular to the pressure receiving surface 210, the remaining inner wall surface 323B of the present embodiment is provided with a first vertical surface 325, a parallel stepped surface 326, an inclined surface 327, and a second vertical surface 328 in this order from the opening side of the housing recess 32. The opening side of the housing recess 32 corresponds to the rear side L2 of the axial direction L. The first vertical surface 325 is located on the rearmost side L2 of each remaining inner wall surface 323B and is formed perpendicular to the pressure receiving surface 210. The parallel stepped surface 326 is formed adjacent to the end of the pressure receiving side L1 of the first vertical surface 325 in each remaining inner wall surface 323B.

The inclined surface 327 is formed adjacent to an end of the parallel stepped surface 326 of each remaining inner wall surface 323B and is positioned inward toward the pressure receiving side L1, as shown in fig. 8. Inward means the center side of the housing recess 32 in the plane of the pressure receiving surface 210. The inclined surface 327 serves as a guide surface when the sensor unit 2 is fitted into the fitting portion 321 of the housing recess 32. The inclined surface 327 may be formed in a short range as shown in fig. 8, or may be formed in a size to appropriately guide the assembly of the sensor unit 2 as shown in fig. 9.

As shown in fig. 8 and 9, in each remaining inner wall surface 323B, a second vertical surface 328 is formed perpendicular to the pressure receiving surface 210, adjacent to the end of the pressure receiving side L1 of the inclined surface 327. The second vertical surface 328 is provided to define the filling gap 34 filled with the sealing resin 4 between the second vertical surface 328 and the side surface 222 of the molded resin portion 22. In other words, the filling gap 34 filled with the sealing resin 4 is formed between the second vertical surface 328 and the side surface 222 of the molded resin portion 22. Further, as shown in fig. 6, the inner wall surface 323A on the conductive terminal side is formed, for example, perpendicular to the pressure receiving surface 210 without a stepped portion.

(function and Effect)

In the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the sealing resin 4 filled in the case recess 32 covers the surface portion of the molded resin part 22 disposed in the case recess 32. That is, the sealing resin 4 completely covers the rear side portion 222B of the side surface 222 of the molded resin part 22 and the rear surface 223 of the molded resin part 22. With this configuration, in the outer periphery of the sensor unit 2, the interface between the mold resin portion 22 of the sensor unit 2 and the sealing resin 4 is not exposed to the outside, and only the interface between the housing 3 and the sealing resin 4 is exposed to the outside.

The parallel stepped surfaces 326 are formed on three remaining inner wall surfaces 323B other than the inner wall surface 323A on the conductive terminal side, the remaining inner wall surfaces 323B forming the case recess 32 to surround the side surface 222 of the molded resin portion 22 of the sensor unit 2. With this configuration, even if peeling occurs at the interface between the first vertical surface 325 of the remaining inner wall surface 323B of the housing 3 and the sealing resin 4 facing the first vertical surface 325, the parallel stepped surface 326 can prevent such peeling from being extended.

In fig. 8, the case where peeling occurs at the interface between the first vertical surface 325 and the sealing resin 4 is shown by the alternate long and short dashed lines X. In this case, although the sealing resin 4 is separated from the first vertical surface 325 by peeling, the amount of the sealing resin 4 separated from the first vertical surface 325 becomes smaller toward the pressure receiving side L1. When the sealing resin 4 attempts to separate from the first vertical surface 325 in a direction parallel to the pressure receiving surface 210 of the pressure receiving portion 21 (i.e., a direction perpendicular to the axial direction L), the sealing resin 4 facing the parallel stepped surface 326 is in a state difficult to separate from the parallel stepped surface 326. Therefore, even if peeling occurs between the first vertical surface 325 and the sealing resin 4, the extension of the peeling can be prevented by the parallel stepped surface 326.

Therefore, the pressure sensor 1 of the evaporated fuel leak detector according to the present embodiment can prevent the spread of peeling at the interface between the first vertical surface 325 and the sealing resin 4, and can sufficiently improve the airtightness of the pressure sensor 1.

Next, the inclined stepped surface 326X shown in fig. 10 will be described.

In the example shown in fig. 10, instead of the parallel stepped surface 326 on each remaining inner wall surface 323B of fig. 8, an inclined stepped surface 326X having an inner angle θ inclined less than 90 degrees with respect to the pressure receiving surface 210 may be formed. The interior angle θ is an angle between the first vertical surface 325 and the inclined stepped surface 326X. Since the acute included angle θ is formed between the first vertical surface 325 and the inclined stepped surface 326X, the peeling generated between the first vertical surface 325 and the sealing resin 4 can be prevented from proceeding toward the pressure receiving side L1 as in the parallel stepped surface 326.

In each remaining inner wall surface 323B of the housing recess 32, the inclined surface 327 may not be formed between the first vertical surface 325 and the parallel stepped surface 326. For example, the first vertical surface 325, the parallel stepped surface 326, and the second vertical surface 328 may be formed in this order from the rear side L2 of the housing recess 32. Even in this case, an effect of preventing the peeling extension due to the parallel stepped surface 326 can be obtained. Further, an inclined step surface 326X may be used instead of the parallel step surface 326.

Further, a parallel step surface 326 or an inclined step surface 326X may be formed in the inner wall surface 323A on the conductive terminal side. Therefore, even when peeling occurs at the interface between the inner wall surface 323A on the conductive terminal side and the sealing resin 4, the extension of the peeling can be prevented by the parallel step surface 326 or the inclined step surface 326X. The parallel stepped surface 326 or the inclined stepped surface 326X may be formed only in a portion of the remaining inner wall surface 323B.

The other configurations, functions, and effects of the evaporated fuel treatment device 1 of the present embodiment are the same as those of the first embodiment. In this embodiment, components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

< third embodiment >

The pressure sensor 1 of the third embodiment is different from the pressure sensor of the first embodiment or the second embodiment, in particular, the shape of the housing 3. As shown in fig. 11 to 13, the pressure sensor 1 of the third embodiment also includes a sensor unit 2, a housing 3, and a sealing resin 4. Each remaining inner wall surface 323B of the housing recess 32 of the present embodiment is provided with a first vertical surface 325, an inclined surface 327, and a second vertical surface 328 in this order in a cross section along the axial direction L perpendicular to the pressure receiving surface 210. The inclined surface 327 is inclined inward as it goes toward the pressure receiving side L1. The second vertical surface 328 extends from the end of the pressure receiving side L1 of the inclined surface 327 to define the filling gap 34, in which the sealing resin 4 is filled between the side surface 222 of the molding resin portion 22 and the second vertical surface 328. The inclined surface 327 and the second vertical surface 328 are formed on a plurality of remaining inner wall surfaces 323B that intersect with each other.

The filling gap 34 may be formed to have a regular thickness within the distance in the axial direction L between the pressure receiving side L1 and the rear side L2 such that the amount of change in thickness is in the range of, for example, 0.5 mm. Further, the filling gap 34 may be formed in a thickness range of, for example, 0.5 to 2 mm.

In the present embodiment, as shown in fig. 14, in a cross section along the axial direction L perpendicular to the pressure receiving surface 210, an end portion 327A of the inclined surface 327 on the pressure receiving side L1 is positioned at a rear side L2 parallel to the outer edge portion 224 of the pressure receiving surface 210 of the molded resin section 22 in the axial direction L. The difference between the positions of the end portion 327A and the outer edge portion 224 in the axial direction L is indicated by reference sign S. As a result, when the molded resin part 22 of the sensor unit 2 is fitted into the fitting part 321 of the housing recess 32, the molded resin part 22 is fitted into the fitting part 321 after being guided to the standard fitting position by the inclined surface 327.

The sealing resin 4 is filled up to the end portion 327B on the rear side L2 beyond the inclined surface 327 of each remaining inner wall surface 323B on the rear side L2. In other words, the outer surface of the sealing resin 4 is located on the rear side L2 beyond the end 327B on the rear side L2 of the inclined surface 327. The entire inclined surface 327 of each remaining inner wall surface 323B is embedded in the sealing resin 4.

Further, as shown in fig. 11 and 12, the sealing resin 4 covers the entire rear surface 223 of the molded resin part 22 and the entire rear side portion 222B of the side surface 222 of the molded resin part 22, except for the pressure-receiving side portion 222A in the side surface 222 of the molded resin part 22. By filling the sealing resin 4 to a position of the rear side L2 beyond the inclined surface, the thickness of the sealing resin 4 disposed on the rear side L2 of the molding resin section 22 can be made equal to or greater than a certain thickness.

As shown in fig. 14, in a cross section along the axial direction L perpendicular to the pressure receiving surface 210, the remaining inner wall surface 323B of the receiving recess 32 of the present embodiment is provided with a first vertical surface 325, an inclined surface 327, and a second vertical surface 328 in this order from the rear side L2 of the receiving recess 32. The configuration of the first vertical surface 325, the inclined surface 327, and the second vertical surface 328 is similar to that of the second embodiment. However, the parallel stepped surface 326 or the inclined stepped surface 326X may be formed between the first vertical surface 325 and the inclined surface 327, as in the example illustrated in fig. 8 to 10.

(function and Effect)

In the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the sealing resin 4 filled in the case recess 32 covers the surface portion of the molded resin part 22 disposed in the case recess 32. That is, the sealing resin 4 completely covers the rear side portion 222B of the side surface 222 of the molded resin part 22 and the rear surface 223 of the molded resin part 22. With this configuration, electromagnetic noise or heat generated from the motor of the pressure-reducing pump 51 and solenoid noise of the solenoid valve 52 arranged around the pressure sensor 1 of the pressure-reducing leak check module 10 are difficult to reach the sensor unit 2 from the rear side L2 of the sensor unit 2.

Each remaining inner wall surface 323B of the housing recess 32 of the present embodiment is provided with a first vertical surface 325, an inclined surface 327, and a second vertical surface 328 in this order in a cross section in the axial direction L perpendicular to the pressure receiving surface 210. The inclined surface 327 is inclined inward as it goes toward the pressure receiving side L1. The second vertical surface 328 extends from the end of the pressure receiving side L1 of the inclined surface 327 to define the filling gap 34, in which the sealing resin 4 is filled between the side surface 222 of the molding resin portion 22 and the second vertical surface 328. With this configuration, the thickness of the sealing resin 4 filled in the filling gap 34 between the side surface 222 and the second vertical surface 328 of the molding resin section 22 is substantially uniform between the pressure receiving side L1 and the rear side L2 in the axial direction L.

In fig. 14, the thickness of the sealing resin 4 filled in the filling gap 34 slightly changes in the axial direction L due to the tapered shape of the rear side portion 222B of the side surface 222 of the molding resin section 22. In this case, however, the amount of change in the thickness of the sealing resin 4 filled in the filling gap 34 is smaller than the amount of change in the width of the sealing resin 4 due to the inclination angle of the inclined surface 327.

Due to the configuration in which the thickness of the sealing resin 4 filled in the filling gap 34 is substantially uniform, when the pressure sensor 1 is heated or cooled, the thermal stress applied from the sealing resin 4 to the sensor unit 2 in the direction perpendicular to the axial direction L is substantially uniform at each portion in the axial direction L.

In the present embodiment, the linear expansion coefficient of the sealing resin 4 is made larger than the linear expansion coefficient of the molding resin portion 22 of the sensor unit 2. When the pressure sensor 1 is heated, the amount of expansion of the sealing resin 4 becomes larger than the amount of expansion of the molding resin part 22, so that thermal stress is applied from the sealing resin 4 filled in the filling gap 34 to the sensor unit 2 including the pressure receiving part 21 and the molding resin part 22. At this time, the thermal stress is proportional to the thickness of the sealing resin 4. However, in the present embodiment, by making the thickness of the sealing resin 4 filled in the filling gap 34 substantially uniform, it is possible to make the thermal stress acting on the sensor unit 2 from the sealing resin 4 substantially uniform. In this way, since the thermal stress applied to the sensor unit 2 becomes substantially uniform, it is possible to prevent uneven deformation from occurring in the sensor unit 2.

Therefore, according to the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the stress acting on the pressure receiving unit 21 due to the deformation of the sensor unit 2 can be reduced, and the pressure detection at the pressure receiving unit 21 can be accurately performed.

Further, the inclined surface 327 and the vertical surface 328 may be formed at least on the two remaining inner wall surfaces 323B perpendicular to each other, so that the sensor unit 2 is effectively guided into the fitting portion 321 of the housing recess 32 using the inclined surface 327. If the two inclined surfaces 327 are provided in the remaining inner wall surfaces 323B perpendicular to each other, the position of the sensor unit 2 with respect to the fitting portion 321 can be adjusted to be positioned in a plane parallel to the pressure receiving surface 210.

Other configurations, functions, and effects of the pressure sensor 1 of the present embodiment are similar to those of the first embodiment or the second embodiment. In the above third embodiment, components denoted by the same reference numerals as those in the first embodiment or the second embodiment may have the same structures as those in the first embodiment or the second embodiment.

< fourth embodiment >

The pressure sensor 1 of the fourth embodiment is different from the pressure sensors of the first and third embodiments, particularly in the shape of the housing 3. As shown in fig. 15 to 18, the pressure sensor 1 of the fourth embodiment also includes a sensor unit 2, a housing 3, and a sealing resin 4. A buffer recess 35 having an outer shape larger than that of the pressure receiving surface 210 is formed at the pressure receiving side L1 of the bottom of the housing recess 32 of the present embodiment. The buffer recess 35 is continuously formed at the pressure receiving side L1 of the housing recess 32, and is disposed on the pressure receiving side L1 instead of the sensor unit 2 in a state where the sensor unit 2 is fitted in the fitting portion 321 of the housing recess 32.

As shown in fig. 15, 16 and 18, a protruding cylindrical portion 36 protruding into the buffer recess 35 toward the rear side L2 is formed on the rear side L2 at the outer edge of the opening end portion of the fluid flow path 31. The buffer recess 35 is formed in an annular shape surrounding the protruding cylindrical portion 36. The housing recess 32 may be deeply formed to be recessed deeper on the pressure receiving side L1 to have the buffer recess 35, thereby forming the protruding cylindrical portion 36 on the outer edge of the opening end portion of the fluid flow path 31 on the rear side L2. The protruding cylindrical portion 36 has a tubular shape, and the fluid flow path 31 is formed longer on the rear side L2 by the amount of the protruding cylindrical portion 36 formed.

As shown in fig. 15 and 18, the bottom surface 351 facing the mold resin portion 22 of the sensor unit 2 is formed at a bottom position of the pressure receiving side L1 of the housing recess 32 where the buffer recess 35 is not formed. The buffer recess 35 may be formed in various shapes surrounding the protruding cylindrical portion 36.

As shown in fig. 15 and 16, the pressure receiving surface 210 of the pressure receiving portion 21 of the sensor unit 2 is positioned on the rear side L2 from the end face 221 of the pressure receiving side L1 of the molded resin portion 22. Then, the pressure receiving surface 210 of the pressure receiving portion 21 is in a state of being pulled toward the rear side L2 and being recessed into the molding resin portion 22. Further, the pressure receiving portion 21 is surrounded and protected by the molded resin portion 22.

A fluid passage gap 37 through which the fluid "R" passes is formed between an end portion of the rear side L2 of the protruding cylindrical portion 36 and the end surface 221 of the pressure receiving side L1 of the sensor unit 2. Due to the formation of the protruding cylindrical portion 36, the dimension (i.e., the width) of the fluid passage gap 37 in the axial direction L is smaller than the depth from the end face 221 of the pressure receiving side L1 of the molding resin portion 22 to the bottom surface of the pressure receiving side L1 of the relief recess 35.

As shown in fig. 15 to 17 of the present embodiment, fitting gaps 39 are provided between the periphery of the end portion of the pressure receiving side L1 of the molded resin portion 22 and the remaining inner wall surface 323B of the case concave portion 32 in the three directions. The pressure-receiving side portion 222A of the molded resin part 22 is guided by the convex portion 38 formed in the fitting portion 321 of the housing concave part 32, and is fitted into the fitting portion 321 of the housing concave part 32. The shape of the convex portion 38 is easily changed by adjusting the shape of a molding die for molding the housing 3. Therefore, the size of the fitting clearance 39 can be easily adjusted.

(function and Effect)

In the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the buffer recess 35 is formed at the pressure receiving side L1 of the bottom of the housing recess 32, and is positioned between the housing recess 32 and the fluid flow path 31. Further, a protruding cylindrical portion 36 that protrudes into the buffer recess 35 toward the rear side L2 is formed at the outer edge of the opening end portion of the fluid flow path 31 on the rear side L2.

When the sealing resin 4 is filled in the housing recess 32 in which the sensor unit 2 is arranged, a part of the sealing resin 4 may flow from the housing recess 32 toward the fluid flow path 31 through the fitting gap 39. Even in this case, a part of the sealing resin 4 is blocked by the protruding cylindrical portion 36, and a part of the sealing resin 4 can be stored in the buffer concave portion 35. Therefore, a part of the sealing resin 4 can be prevented from flowing out to the fluid flow path 31.

If a part of the sealing resin 4 flows into the fluid flow path 31, the air flow resistance of the fluid flow path 31 increases, and the responsiveness detected by the pressure sensor 1 may decrease. Further, in this case, the orifice 541 may be clogged with a part of the sealing resin 4. Therefore, the detection accuracy of the leak check of the pressure-reducing leak check module 10 may be lowered.

In the present embodiment, since the sealing resin 4 can be stored in the buffer concave portion 35, the detection accuracy of the leak check of the pressure-reducing leak check module 10 can be effectively improved. The orifice 541 can be prevented from being blocked by the sealing resin 4 flowing from the receiving recess 32 toward the fluid flow path 31, and the sealing resin can be prevented from adhering to the pressure receiving surface 210 of the pressure receiving portion 21. As a result, the responsiveness of the pressure sensor 1 can be improved, and the detection error of the pressure sensor 1 can be effectively prevented. Therefore, the detection accuracy of the leak inspection of the pressure-reducing leak inspection module 10 can be improved. Further, since the sealing resin 4 can be stored in the buffer concave portion 35, a certain amount of the sealing resin 4 can be allowed to flow out from the housing concave portion 32 to the side of the fluid flow path 31.

In the present embodiment, since the pressure-receiving side portion 222A in the side surface 222 of the molded resin part 22 is fitted into the housing recess 32, it is not necessary to use a concave-convex fitting structure between the molded resin part 22 and the housing recess 32. Therefore, the damage of the molded resin portion 22 can be effectively prevented.

Therefore, according to the pressure sensor 1 of the evaporated fuel leak detector of the present embodiment, the molded resin portion 22 of the sensor unit 2 can be protected, and the pressure can be accurately detected even when the sealing resin 4 flows out from the case concave portion 32.

Other configurations, functions, and effects of the pressure sensor 1 of the present embodiment are similar to those of the first to third embodiments. In the above fourth embodiment, components denoted by the same reference numerals as those in the first to third embodiments may have the same structures as those in the first to third embodiments.

In the first to fourth embodiments, the pressure sensor 1 is applied to the pressure-reducing leak check module 10. Besides, the pressure sensor 1 may be applied to a positive pressure leak inspection module that performs a leak inspection in a pressurized state.

The present embodiment is described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Modifications or changes to these specific examples, as appropriate, by those skilled in the art, are also included within the scope of the present disclosure as long as they have the characteristics of the present disclosure. Each element contained in the respective specific examples described above, and the arrangement, condition, shape, and the like of these elements are not limited to those illustrated, and may be changed as appropriate. The respective elements included in the above-described specific examples may be appropriately combined as long as there is no technical contradiction therebetween.

Claims

1. A pressure sensor for an evaporated fuel leak detector configured to detect a leak of evaporated fuel in an evaporated fuel treatment apparatus (6), the evaporated fuel treatment apparatus (6) including a fuel tank (61) and a canister (62) for adsorbing evaporated fuel discharged from the fuel tank, the pressure sensor comprising:

a sensor unit (2) including a pressure receiving portion (21) configured to detect a pressure of a fluid applied to a pressure receiving surface (210), a plurality of conductive terminals (213) provided at the pressure receiving portion and made of a conductive material, and a molded resin portion (22) covering an outer surface of the pressure receiving portion other than the pressure receiving surface (210);

a housing (3) provided with a fluid flow path (31) through which a fluid is introduced to the pressure receiving surface and a housing recess (32) which accommodates the sensor unit therein and is connected to the fluid flow path; and

a sealing resin (4) filled in the housing recess accommodating the sensor unit to cover a surface of the mold resin part disposed in the housing recess, wherein,

the housing has an annular inner wall surface (323) that defines the housing recess and surrounds a side surface (222) of the molded resin portion, and the annular inner wall surface of the housing includes a first inner wall surface (323A) on a conductive terminal side where a plurality of conductive terminals are arranged and a plurality of second inner wall surfaces (323B) that intersect each other, and

when a direction of the housing recess in which the pressure receiving surface is arranged to be exposed from the housing recess is a pressure receiving side (L1) and a direction opposite to the pressure receiving side of the housing recess is a rear side (L2), in a cross section along a direction perpendicular to the pressure receiving surface, the second inner wall surface has an inclined surface (327) inclined inward as it goes toward the pressure receiving side, and a vertical surface (328) adjacent to the pressure receiving side of the inclined surface, the vertical surface (328) extending in the direction perpendicular to the pressure receiving surface to define a sealing resin-filled gap (34) between the side surface of the molded resin section and the vertical surface.

2. The pressure sensor of claim 1,

an end portion of the inclined surface on the pressure receiving side is positioned on the rear side beyond an outer edge portion (224) of the molded resin portion in a plane parallel to the pressure receiving surface in a cross section along a direction perpendicular to the pressure receiving surface,

the side surface (222) of the molded resin section has a pressure-receiving side portion (222A) adjacent to the pressure-receiving surface and a rear side portion (222B) other than the pressure-receiving side portion,

the pressure-receiving side portion of the side surface of the molded resin part is fitted into the housing recess, an

The sealing resin is filled in the case recess to a position beyond the rear side from the inclined surface to cover all rear surfaces of the molded resin part and a rear side part (222B) of the molded resin part other than the pressure-receiving side part.

3. The pressure sensor of claim 1 or 2,

the inclined surface and the vertical surface are provided at least on two second inner wall surfaces perpendicular to each other.